Method of forming continuous strip of bags



United States Patent Inventor Appl. No. Filed Patented Emanuel Kugler124 Richmond Place, Lawrence, New York 1 1559 Feb. 3, 1967 Oct. '13,1970 Continuation-impart of Ser. No. 417,402, Dec. 10, 1964, nowabandoned, which is a continuation of Ser. No. 336,830, Jan. 9, 1964,now abandoned. 1

METHOD OF FORMING CONTINUOUS STRIP OF BAGS 2 Claims, 10 Drawing Figs.

US. Cl 93/35, 93/33 Int. Cl B3lb 1/14, B3 1 b 49/04, B3 lf7/00 Field ofSearch 93/31 35(PCO) [56] References Cited UNITED STATES PATENTS2,212,469 8/1940 French 93/33 3,060,075 10/1962 Kincaid 93/35 FOREIGNPATENTS v751.339 6 1956 GreatBritain............ 93/351001 825.61012/1959 GreatBritain 93/35lCPO) Primary Examiner-Wayne A. Morse, Jr.Attorney-Amster and Rothstein ABSTRACT: A continuous length of limpthermoplastic material, tubular in form, is fed from a supply, a seriesof pairs of registered lines of perforations are formed in the walls ofthe length, the walls are heat sealed at spaced intervals near the pairsof lines of perforations. and then one wall is moved relative to theother wall to tear the lines of only one wall to form open slit mouthsfor the connected bags.

on one side wall of said bag strip parallelly spaced with respect toeach other, and arranged in a fan fold configuration.

The present invention is useful not only in making bags of theconventional type but in making bags of a novel nature to be hereinafterdescribed in which the bags in a continuous stack are ready for filling.

In accordance with the present invention, tubular material is scored orotherwise weakened from edge to edge at longitudinally spaced intervalsequal to the overall length of the desired bag to provide readyseverability in such a manner that the lines of severance will definethe respective bags. After the tubular strip is thus scored or weakened,opposite sides of the tube are sealed together along lines closelyadjacent the respective lines of severability to form-bottoms of therespective bags. Finally, one of the walls of the tubular strip isseparated and broken at each of the lines of severability. The oppositewall of the tubular strip is left intact, however, so that each of thebags remain on one continuous strip until desired. The separation in oneof the walls along the lines of severability provide a filling openingfor each of the bags so that the said bags may be conveniently openedand filled without the necessity of separating the bag from the stackprior to filling, and without the use of such expedients as staples,rivets, hot needles, wickets, clamps or the like.

Thus, a continuous bag strip is provided which comprises a multiplicityof interconnected preformed bags which may be individually severed fromthe bag strip at the weakened or scored lines. This not only provides agreatly improved method of manufacture resulting in substantialeconomies, but also makes it possible to facilitate packing, handling,storage, shipping and dispensing the bags individually as they arerequired ,for either manual or machine filling.

Of great importance to this invention is the apparatus utilized toseparate one wall only of the tubular strip along the lines ofseverability without damaging or separating the said opposite wall. Thisis essentially accomplished by utilizing a pair of members contactingthe moving tubular strip. The said members urge the said strip togetherby exerting pressure thereon. The member contacting the wall of thetubular strip desired to be severed advances at a greater speed thanthat of the said tubular strip. The opposite member will move atsubstantially the same speed as that of the advancing tubular strip.Thus, the faster member will urge one of the walls of the tubular stripto move relative to the opposite said wall, thereby causing a break inthe desired wall of the tubular strip along its scored or weakened linesof severability. The above-described operation is repeated for each bagin turn, thus providing a filling opening for each said bag. Of course,the important feature herein is the relative movement of one wall to theother, even though that movement may be forward, rearward, up. down, orto the side.

In one embodiment of this invention, the said members will be comprisedof a pair of rollers, one moving at a greater speed than that of theother.

Further, the fan fold stacking of the formed bags is of specialimportance.

With these objects in view the invention consists of the novel featuresof construction and arrangement of parts which will appear in thefollowing specification and recited in the appended claims, referencebeing had to the accompanying drawings in which the same referencenumerals indicate the same parts throughout the various figures, and inwhich:

FIG. 1 is a plan view showing one face of a section of a bag stripillustrating one step of the instant invention.

FIG. 2 is a plan view showing one face of a section of a bagillustrating a second step of the instant invention.

FIG. 3 is a plan view showing one face of a section of a bag stripillustrating a final step of the instant invention.

FIG. 4 is a sectional view taken substantially along line 4-4 of FIG.1.

FIG. 5 is a sectional view taken substantially along line 5-5 of FIG. 2.

FIG. 6 is a sectional view taken substantially along line 6-6 of FIG. 3.

FIG. 7 is a sectional view illustrating diagrammatically the steps ofcarrying out the instant invention.

FIG. 8 is an elevational view primarily diagrammatically showing onemethod of utilizing the product of the instant invention.

FIG. 9 is a fractional plan view showing one alternate embodiment of theinvention.

FIG. 10 is an elevational view of an alternate apparatus for separatingthe lines of weakness in one wall of the strip.

Referring to FIGS. 1 through 7, a bag strip 21 is shown from whichindividual preformed bags such as 22 may be severed. The bag strip 21has a front wall or panel 19 and a rear wall or panel 20 formed into atube of relatively thin polyethylene or other flexiblethermoplastic-like material. The term thermoplastic material as hereinused is to be understood as meaning plastic material which may be heatsealed to effect the sealing together of various portions of the strip21 as described below. Strip 21 is providedwith a series of transverselyextending longitudinally spaced substantially parallel severance or tearlines, such as 24, extending from edge to edge of the strip and formedby any suitable means such as by scoring or perforating the materialalong these lines so that upon application of proper force, the bagstrip 21 may be readily separated along the tear lines 24 to form thebags such as 22, as described below.

In the diagrammatic FIG. 7 there is shown schematically in elevation,several of the steps in accomplishing the instant invention. The strip21 of tubular thermoplastic material may be advanced as from a roll ofsuch material. of course, the said tubular strip 21 may be provided inany known fashion. The tubular strip 21 is advanced to a perforating die101. The said die will have minute projections 102 extending therefromand will be adopted to periodically descend against the strip 21. Thus,as the projections 102 periodically contact the said tubular strip 21they will provide the severance tear lines through both walls 19 and 20of the tubular strip 21.

It is to be noted that although the tubular formation 21 illustratedherein is relatively plain, other forms of tubular strips may beprovided. For example, suitable gussets may be provided at either sideof the said strip 21, or the said strip may have various embellishmentsthereon such as heat sealed portions, etc. Additionally, the said strip21 may initially be provided as a flat sheet, and the perforations may,if desired, be provided while the material still is in the flattenedsheet condition. In such an embodiment of this invention, the said stripwill-be folded about a fold line until its longitudinal edges arebrought into overlapping engagement. The said edges may then be heatsealed along a longitudinal seam or sea] line to complete the tubularformation.

No matter how provided, however, the said tubular strip 21 will besealed at longitudinally spaced substantially parallel transverse seallines 27 closely adjacent the respective tear lines 24 to provide thebottom seals of respective bags.

In the diagrammatic FIG. 7, the said transverse seal lines 27 are shownas being provided by a heat sealing bar 103. The said bar 103 has asuitable heat sealing portion I05 thereon. The said heat sealing bar 103may be elevated to a desired temperature as by resistance electricalmembers. The heat sealing bar 103 will periodically contact the walls 19and 20 of the strip 21 thereby heat sealing the said walls togetheralong parallel transverse seal lines 27.

Again, it should be noted that as in the previous steps, this step isshown only schematically and any well known heat sealing means may besubstituted therefor.

It is now necessary, however, to separate one of the walls 19periodically in order to provide a filling opening for each of the bags,while the said bags are still in a continuous strip. To

accomplish the same, there is shown as the final step in FIG. 7, v

a pair of pressure or draw rollers 109 and 110. The said rollers 109 and110 will be driven at a carefully controlled speed. Further, they willbe biased toward each other so as to exert a controlled pressure uponthe said moving tubular strip 21. As

will be noted, one of the said rollers 109 is substantially larger thanthe corresponding roller 110. Assumingthat the central shafts of each ofthe said rollers 109 and 110 are driven at an equal speed of rotation,the periphery of the larger roller 109 will be moving at a greatertangential speed than that of the corresponding smaller roller 110.Assuming further that the said smaller roller 110 is moving at acarefully calculated speed so that the periphery of the said roller willbe advancing at the same tangential speed as that of the tubular strip21, the roller 109 will tend to move one of the walls 19 of the saidtubular strip 21 relative to the other. it is well known thatthermoplastic materials such as polyethylene are relatively smooth andwill tend to slip. Thus, the said wall 19 of the tubular strip 21 in thearea of this roller 109 and 110 will move slightly relative to the saidopposite wall 20 of the tubular strip 21, thereby causing a tear in thesaid wall 19. In that there is a weakened line 24 provided in the saidwall 19, the wall 19 will tear along the line of weakness 24.

Thus, as each bag length in turn passes by the rollers 109 and 110, oneof the walls 19 of the strip 21 will be torn along its lines ofweakness. As the tubular strip 21 passes the rollers 109 and 110, itwill, therefore, consist of a continuous length of material 20 havingsealed thereto discontinuous lengths of material 19 forming individualbags with an opening opposite the heat sealed edge of the bag.Immediately thereafter, the now formed continuous bag strip 21 will befan folded as at 120 to be held for use. it is desirable to urge thestrip 21 into the fan fold 120 in a position closely spaced to that ofthe pressure rollers 109 and 110 to prevent distortion of the said strip21. The strip 21 as previously mentioned will have one continuous walland one discontinuous wall. As most thermoplastic materials will stretchand yield under tension, the

continuous wall 20 may distort if there is tension or pressure thereon.To avoid the same, immediate folding is preferable.

There are other ways in which to move one wall of the tubular strip 21relative to the other wall of the strip in order to separate said wallat its lines of weakness 24, rather than by the use of the two rollers109, 110 shown in FlG. 7. Such an alternate form is illustrated in FIG.wherein the strip 21 passes along a table 107 formed typically of hardrubber or metal. When each line of weakness 24 in the wall 19 in turnpasses by a predetermined location, that is, under an elongated rod 111,the rod is reciprocated transversely ofthe strip. The rod 111 isconnected by a link 113 to a cam wheel 115 fast on a driven shaft 117.The link 113 is rotatably mounted on and offset with respect to thewheel whereby as the wheel 115 rotates, the rod 111 reciprocates. Thelink is retained in its transversely extending path by a pair of guides119 on either end thereof. The rod carries, along its bottom surface, arubber pad 121 which presses the strip against the table 107 and rubs orscuffs the upper wall 19 along a line of weakness 24 in the strip,thereby severing the same but leaving the bottom wall untorn. The guides119 are mounted on solenoids 121 which lift the rod upwardly away fromthe strip 21 to permit the strip to advance. When the next line ofweakness reaches a location below the rod, the solenoids 121 lower therod to permit the same to act on said line of weakness.

The weakened lines of severance 24 permit individual bags to be readilysevered from the bag strips 21, either by exerting pressure, as by astraight, quick pull, or in any other conventional manner. Prior toseverance, each of the individual bags will have a filling opening 130adjacent the line of severance of that bag from the strip 21.

This makes it possible to fill bags of this type much more expeditiouslyand economically than is possible in prior art devices. For example, asshown in the diagrammatic FIG. 8, the stack of finished bags 120 may beunfolded in any convenient manner, as by a pair of draw rollers 131 and132. The strip 21 may then pass over a bar 134 so that the one baglength will hang downward. When in that position, the opening 130 in thewall 10 of the bag will be at the top of the bag facing upward. Anyconvenient hopper 138 may be utilized to fill the said bag. When the bagis filled, it will be torn from the strip 21 and lowered as onto aconveyor belt or the like (not illustrated). Thus, the fan fold stack ofbags may be easily filled. Large numbers of bags preformed in acontinuous strip of any desired length may be unwound from the stack tofacilitate handling, packing, storage and shipping.

Additionally, other means of various types may be utilized to fill anddispense the bags. for example, the strip 21 can be mounted in asuitable dispenser, such as for example, dispensers in which stacks ofpaper tissues and the like material are mounted and the individual bagssevered from a bag strip fan fold as needed.

No matter what be the filling means, however, the essential feature ofthe invention is the provision of a continuous bag strip having lines ofweakness with one of the walls discontinuous thereby providing openingsto each of the bags, and the stacking of the bags in a fan foldconfiguration.

The stacking of the bags in a fan fold configuration is an especiallyimportant feature of this invention. It permits the bags to remain in acontinuous stack without tension being placed on any but the bags beingremoved. lf, for example, the bags were positioned on a roll or thelike, in a continuous strip, tension on one bag would be transmittedrearward to other bags on the roll. However, it will be noted that thefinished strip of this invention provides bags interconnected only byperforations through one wall of the bag. In view of the delicatematerial usually utilized in the fabrication of such bags, it is notconsidered good practice to place such bag strips in tension for anylength of time as they will soon stretch and possibly tear along theline of perforations. Any premature tearing will cause inefficienciesand possibly rethreading of the filling machine.

The fan fold arrangement described herein insures that the major portionof the stack is not under tension at any time. When the bags areunwound, the only tension on the bags not being filled may be due totheir own weight, which is usually insignificant. Thus, the fan folddescribed herein provides a useful adaptation of the invention andinsures proper operation thereof.

There is shown in FIG. 9 an alternate embodiment of the invention. Theconstruction of the bags of FIG. 9 is as described hereinbefore exceptfor the provision ofa slit partially across the continuous wall of thestrip. The line of perforations extending across the continuous wall isbroken at the midsection forming a slit 200. This allows a tongue 201 orthe like to extend entirely through the unit to hold the same in placeas desired.

While there are above disclosed but a limited number of embodiments ofthe structure and product of the invention herein presented, it ispossible to produce still other embodiments without departing from theinventive concept herein disclosed, and it is desired, therefore, thatonly such limitations be imposed on the appended claims as are statedtherein,

or required by the prior art.

I claim:

1. A method of forming a continuous strip oflike bags, each bag havingan open slit mouth, said method including the steps of:

a. supplying a continuous length of thin limp flexible thermoplasticmaterial in a tubular form, the length being folded into flattenedcondition so that the length has an elongated first wall and anelongated second wall, the walls being superimposed;

b. advancing the length of material in said folded condition along apath passing through an operative zone;

c. periodically weakening the length of material at the operative zoneso as to form pairs of similar lines of weakness, one line of each pairbeing formed in registry -to the other wall at the operative zone toform evenly therewith in the other wall, said lines extendingtransversely of the length of material and being evenly distant adimension the same as the length of a single bag;

periodically heat sealing one wall of the length of material distantseal lines extending maximumly transversely of the length of materialadjacent the pairs of lines of weakness, each heat seal lineconstituting the bottom seam for a different bag; and

. then passing the length of material between a pair of rollers, theaxes of the rollers being substantially parallel to one another andsubstantially parallel to the lines of weakness and driving the rollersat different peripheral velocities so as to urge one wall of the lengthof material relative to the other wall whereby to periodically tear onlysaid one wall at each of its lines of weakness thereby to provide anopen slit mouth for each bag.

A method of forming a continuous strip of like bags, each bag having anopen slit mouth, said method including the steps supplying a continuouslength of thin limp flexible thermoplastic material in a tubular form,the length being folded into flattened condition so that the length hasan elongated first wall and an elongated second wall, the

' walls being superimposed;

b. advancing the length of material in said folded conditionperiodically heat sealing one wall of the length of material to theother wall at the operative zone to form evenly distant seal linesextending maximumly transversely of the length of material adjacent thepairs of lines of weakness, each heat seal line constituting the bottomseam for a different bag; and

. then driving an elongated member transversely of the length ofmaterial, said member being in contact with one wall of the lengthadjacent a line of weakness whereby to periodically tearonly said onewall at each of its lines of weakness so as to provide an open slitmouth for each bag.

